Question

Colorblindness is an X-linked recessive disorder. If Abby has normal vision (but her father was colorblind) and Ryan is not colorblind. What are the chances that their daughter is colorblind? SHOW ALL WORK FOR CREDIT. (To insert a table in your answer if necessary click on the three dots, click on the icon that looks like a table and you can customize the number and type of boxes you need)​

Answer 1

Let ‘Xᶜ’ be the recessive allele for colour blindness and ‘X’ be the normal (dominant) allele.

Since Abby's father was colour blind, Abby must be a carrier for the same.

Which means Abby's genotype would be ‘XXᶜ’.

Now, Ryan is not colourblind which means his genotype would be ‘XY’.

Now, talking about their daughter, she would inherit a normal ‘X’ from Ryan and either ‘X’ or ‘Xᶜ’ from Abby.

Which means she wouldn't be colourblind but she might be a carrier of the disorder.

XXᶜ × XY

⬇️ ⬇️

X, Xᶜ X

↘️ ↙️

XX , XXᶜ

Their daughter will have either XX genotype or XXᶜ genotype.

And her chances of being colourblind thus, becomes zero.